Pro-Apoptotic Effects of Plasma from Patients with Cardiorenal Syndrome on Human Tubular Cells.

BACKGROUND: The pathophysiology of Cardiorenal Syndrome Type 1 (CRS1) is widely studied, although the mechanisms by which renal tubular epithelial cells (TECs) cease to proliferate and embark upon terminal differentiation, following the initial insult of heart failure (HF), remain a key target. This study seeks to provide insight into the pathophysiological pathways in CRS1; we evaluated in vitro the effects of CRS1 plasma on TECs. METHODS: We enrolled 40 acute HF patients and 15 controls (CTR) without HF or acute kidney injury (AKI). Ten out of 40 HF patients exhibited AKI at the time of admission for HF or developed AKI during hospitalization and were classified as CRS1. In vitro, cell viability, DNA fragmentation and caspase-3 levels were investigated in TECs incubated with HF, CRS1, and CTR plasma. We assessed inflammatory cytokines and NGAL expression at the gene and protein levels. RESULTS: We observed a marked pro-apoptotic activity and a significantly increased in vitro level of apoptosis in TECs incubated with plasma from CRS1 patients compared to HF and CTR (p < 0.01). In the CRS1 group, the mRNA expression of IL-6, IL-18 and NGAL resulted significantly higher in TECs incubated with CRS1 plasma compared with those incubated with plasma from HF and CTR (p < 0.01). IL-6, IL-18, NGAL, and RANTES levels were significantly higher in TECs supernatant incubated with CRS1 plasma compared with HF patients and CTR plasma (p < 0.01). CONCLUSION: In vitro exposure to plasma from CRS1 patients altered the expression profile of TECs characterized by increases in proinflammatory mediators, release of tubular damage markers, and apoptosis.

[Type 1 cardiorenal syndrome and its possible pathophysiological mechanisms]. / Sindrome cardiorenale di tipo 1: possibili meccanismi patofisiologici alla base di questa sindrome.

Cardiorenal syndrome (CRS) type 1, consisting of acute cardiac events leading to acute kidney injury (AKI), is characterized by multiple factors and its pathophysiology is very complex. Given the circulating nature of many inflammatory mediators, it is tempting to examine the immune-mediated mechanism as a mediator of organ crosstalk. In this pilot study, we examined the possible role of immune-mediated mechanisms in the pathogenesis of this syndrome. We enrolled 12 patients with acute heart failure (AHF), 7 patients with type 1 CRS, and 5 healthy volunteers. EDTA plasma samples from the 3 groups were incubated with a monocyte cell line (U937) and cell apoptosis was subsequently evaluated by different methods. In addition, quantitative determination of TNF-alpha, IL-6 and IL-18 production in the supernatants was performed by ELISA. In U937 cells treated with type 1 CRS plasma, the results showed DNA ladder formation with different molecular weight fractions, suggesting the presence of apoptotic events. In fact, quantitative analysis of apoptosis and caspase-3 levels showed significantly higher apoptosis rates in cells incubated with plasma from patients with type 1 CRS (p<0.05). TNF-alpha levels in the supernatants were significantly elevated in both the AHF and type 1 CRS groups compared with control subjects (p<0.05). Furthermore, in patients with type 1 CRS the levels of the proinflammatory cytokines IL-6 and IL-18 were significantly higher than in AHF patients and the control group (p<0.05). This pilot study explores the premise of an immune-mediated process in the pathophysiology of type 1 CRS. These preliminary findings suggest the presence of defective regulation of apoptosis in patients with this syndrome and the involvement of an immune-mediated mechanism in its pathogenesis. Furthermore, inflammatory pathways seem to play a central role in organ crosstalk and may be fundamental to distant organ damage.

Plasma Lipopolysaccharide Concentrations in Cardiorenal Syndrome Type 1.

BACKGROUND: Cardiorenal syndrome (CRS) type 1 is characterized by a rapid worsening of cardiac function that leads to acute kidney injury (AKI). This study evaluated the role of lipopolysaccharide (LPS) in the development of AKI in patients with acute heart failure (AHF) and its relationship with renal parameters, to enable a better comprehension of the pathophysiology of CRS type 1. METHODS: We enrolled 32 AHF patients, 15 of whom were classified as having CRS type 1. Eight of these 15 exhibited AKI at the time of admission (caused by AHF) and the other 7 developed AKI during their stay in hospital (in the first 48 h). We evaluated the plasmatic LPS concentrations as well as conventional (serum creatinine [sCr] and urea) and unconventional (neutrophil gelatinase-associated lipocalin [NGAL] and cystatin C) renal markers. RESULTS: LPS levels were significantly higher in the CRS type 1 patients. No significant difference in LPS level was found in patients who were admitted with AKI and those developed AKI in hospital, but there was a tendency towards a higher level of LPS in CRS type 1 patients admitted with AKI. The LPS concentrations at admission were similar in CRS type 1 survivors (n = 12) and nonsurvivors (n = 3) (p = 0.22). We observed a positive correlation between LPS level and NGAL, Scr at admission and peak Scr during hospitalization and urea at admission. CONCLUSION: CRS type 1 patients present with an increased level of LPS and there is a direct correlation between LPS and renal parameters. This pilot research is the first study to explore the premise of LPS as novel pathophysiological factor in CRS type 1.

Lipopolysaccharide in systemic circulation induces activation of inflammatory response and oxidative stress in cardiorenal syndrome type 1.

BACKGROUND: Cardiorenal syndrome type 1 (CRS type 1) is characterized by a rapid worsening of cardiac function leading to acute kidney injury. In this study, we evaluate the role of lipopolysaccharide (LPS) and various inflammatory markers in the developing acute kidney injury (AKI) in acute heart failure (AHF) patients. METHODS: We enrolled 31 AHF patients and 20 CRS type 1 (the cause of AKI was presumed to be related to cardiac dysfunction) and 17 healthy volunteers without AHF, AKI or CKD, as control group (CTR). We assessed levels of LPS, proinflammatory cytokines (TNF-α, IL-6, IL-18), and oxidative stress marker (myeloperoxidase, MPO). RESULTS: We observed a significant increase in LPS, TNF-α, IL-6, IL-18 and MPO levels in CRS type 1 and AHF group compared to CTR. LPS levels resulted significantly higher in CRS type 1 patients compared with AHF (118.2 pg/mL, IQR 77.8-217.6 versus 13.5 pg/mL, IQR 12.0-17.0, p = 0.008). We found a cytokines and oxidative stress dysregulation in CRS type 1 patients compared with AHF. Furthermore, we observed a strong positive significant correlation between LPS levels and IL-6 (Spearman's rho = 0.79, p < 0.001), and IL-18 (Spearman's rho = 0.77, p < 0.001) and MPO (Spearman's rho = 0.80, p < 0.001), all confirm by simple linear regression analysis. CONCLUSION: CRS type 1 patients presented an increased level of LPS, pro-inflammatory cytokines, and MPO. Furthermore, there is a direct correlation between LPS and pro-inflammatory cytokines and stress oxidative marker. LPS may play a role in the pathophysiology of CRS type 1 inducing inflammation, oxidative stress and finally kidney damage.

Levels of Proinflammatory Cytokines, Oxidative Stress, and Tissue Damage Markers in Patients with Acute Heart Failure with and without Cardiorenal Syndrome Type 1.

BACKGROUND: Cardiorenal syndrome type 1 (CRS type 1) is characterized by a rapid worsening of cardiac function leading to acute kidney injury (AKI). Inflammation and oxidative stress seem to play a pivotal role in its pathophysiology. In this in vivo study, we examined the putative role of inflammation and humoral markers in the pathogenesis of the CRS type 1. METHODS: We enrolled 53 patients with acute heart failure (AHF); 17 of them developed AKI (CRS type 1). The cause of AKI was presumed to be related to cardiac dysfunction after having excluded other causes. We assessed the plasma levels of proinflammatory cytokines (TNF-α, IL-6, IL-18, sICAM, RANTES, GMCSF), oxidative stress marker (myeloperoxidase, MPO), brain natriuretic peptide (BNP), and neutrophil gelatinase-associated lipocalin (NGAL) in AHF and CRS type 1 patients. RESULTS: We observed a significant increase in IL-6, IL-18, and MPO levels in CRS type 1 group compared to AHF (p < 0.001). We found higher NGAL at admission in the CRS type 1 group compared to the AHF group (p = 0.008) and a positive correlation between NGAL and IL-6 (Spearman's rho = 0.45, p = 0.003) and between IL-6 and BNP (Spearman's rho = 0.43, p = 0.004). We observed lower hemoglobin levels in CRS type 1 patients compared to AHF patients (p < 0.05) and inverse correlation between hemoglobin and cytokines (IL-6: Spearman's rho = -0.38, p = 0.005; IL-18: Spearman's rho = -0.32, p = 0.02). CONCLUSION: Patients affected by CRS type 1 present increased levels of proinflammatory cytokines and oxidative stress markers, increased levels of tissue damage markers, and lower hemoglobin levels. All these factors may be implicated in the pathophysiology of CRS type 1 syndrome.

Determinants of Monocyte Apoptosis in Cardiorenal Syndrome Type 1.

BACKGROUND: Cardiorenal syndrome type 1 (CRS type 1) is characterized by a rapid worsening of cardiac function leading to acute kidney injury (AKI). Its pathophysiology is complex and not completely understood. In this study, we examined the role of apoptosis and the caspase pathways involved. MATERIAL AND METHODS: We enrolled 40 acute heart failure (AHF) patients, 11 of whom developed AKI characterizing CRS type 1. We exposed the human cell line U937 to plasma from the CRS type 1 and AHF groups and then we evaluated apoptotic activity by annexin-V evaluation, determination of caspase-3, -8 and -9 levels, and BAX, BAD, and FAS gene expression. RESULTS: We observed significant upregulation of apoptosis in monocytes exposed to CRS type 1 plasma compared to AHF, with increased levels of caspase-3 (p < 0.01), caspase-9 (p < 0.01), and caspase-8 (p < 0.03) showing activation of both intrinsic and extrinsic pathways. Furthermore, monocytes exposed to CRS type 1 plasma had increased gene expression of BAX and BAD (intrinsic pathways) (p = 0.010 for both). Furthermore, strong significant correlations between the caspase-9 levels and BAD and BAX gene expression were observed (Spearman ρ = - 0.76, p = 0.011, and ρ = - 0.72, p = 0.011). CONCLUSION: CRS type 1 induces dual apoptotic pathway activation in monocytes; the two pathways converged on caspase-3. Many factors may induce activation of both intrinsic and extrinsic apoptotic pathways in CRS type 1 patients, such as upregulation of proinflammatory cytokines and hypoxia/ischemia. Further investigations are necessary to corroborate the present findings, and to better understand the pathophysiological mechanism and consequent therapeutic and prognostic implications for CRS type 1.

Oxidative stress: dual pathway induction in cardiorenal syndrome type 1 pathogenesis.

Cardiorenal Syndrome Type 1 (Type 1) is a specific condition which is characterized by a rapid worsening of cardiac function leading to acute kidney injury (AKI). Even though its pathophysiology is complex and not still completely understood, oxidative stress seems to play a pivotal role. In this study, we examined the putative role of oxidative stress in the pathogenesis of CRS Type 1. Twenty-three patients with acute heart failure (AHF) were included in the study. Subsequently, 11 patients who developed AKI due to AHF were classified as CRS Type 1. Quantitative determinations for IL-6, myeloperoxidase (MPO), nitric oxide (NO), copper/zinc superoxide dismutase (Cu/ZnSOD), and endogenous peroxidase activity (EPA) were performed. CRS Type 1 patients displayed significant augmentation in circulating ROS and RNS, as well as expression of IL-6. Quantitative analysis of all oxidative stress markers showed significantly lower oxidative stress levels in controls and AHF compared to CRS Type 1 patients (P < 0.05). This pilot study demonstrates the significantly heightened presence of dual oxidative stress pathway induction in CRS Type 1 compared to AHF patients. Our findings indicate that oxidative stress is a potential therapeutic target, as it promotes inflammation by ROS/RNS-linked pathogenesis.